Le Zhou

Northwest University, Northwest Harborcreek, Pennsylvania, United States

Are you Le Zhou?

Claim your profile

Publications (49)113.23 Total impact

  • International Journal of Molecular Sciences 05/2015; 16(5):9119-9133. DOI:10.3390/ijms16059119 · 2.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper reported the synthesis, structure-activity relationship (SAR) and acaricidal activity in vitro against Psoroptes cuniculi, a mange mite, of 25 ethyl cinnamate derivatives. All target compounds were synthesized and elucidated by means of MS, (1)H- and (13)C-NMR analysis. The results showed that 24 out of 25 tested compounds at 1.0 mg/mL demonstrated acaricidal activity in varying degrees. Among them, 6, 15, 26, 27 and 30 showed significant activity with median lethal concentration values (LC50) of 89.3, 119.0, 39.2, 29.8 and 41.2 μg/mL, respectively, which were 2.1- to 8.3-fold the activity of ivermectin (LC50 = 247.4 μg/mL), a standard drug in the treatment of Psoroptes cuniculi. Compared with ivermectin, with a median lethal time value (LT50) of 8.9 h, 27 and 30 showed smaller LT50 values of 7.9 and 1.3 h, respectively, whereas 6, 15 and 26 showed slightly larger LT50 values of 10.6, 11.0 and 10.4 h at 4.5 μmol/mL. SARs showed that the presence of o-NO2 or m-NO2 on the benzene ring significantly improved the activity, whereas the introduction of a hydroxy, methoxy, acetoxy, methylenedioxy, bromo or chloro group reduced the activity. (E)-Cinnamates were more effective than their (Z)-isomer. Nevertheless, the carbon-carbon double bond in the acrylic ester moiety was proven not to be essential to improve the activity of cinnamic acid esters. Thus, the results strongly indicate that cinnamate derivatives, especially their dihydro derivatives, should be promising candidates or lead compounds for the development of novel acaricides for the effective control of animal or human acariasis.
    CHEMICAL & PHARMACEUTICAL BULLETIN 02/2015; 63(4). DOI:10.1248/cpb.c14-00765 · 1.38 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Thirty-four new 2-aryl-6-chloro-3,4-dihydroisoquinolin-2-ium bromides were synthesized and their structures were elucidated by spectroscopic analysis. Antifungal activities against Alternaria alternate, Curvularia lunata and Valsa mali were evaluated by the mycelium linear growth rate method. SAR was discussed also. All compounds showed some activity against each of the fungi at 25 µg/mL. Compared to azoxystrobin, a commercial fungicide, 31 out of 34 test compounds showed the higher inhibition rates against C. lunata and 10 were more effective against A. alternate and V. mali. Compounds 5-4, 5-2 and 5-34 showed the highest activity against A. alternate (EC50 = 10.3 µg/mL), C. lunata (EC50 = 4.6 µg/mL) and V. mali (EC50 = 3.9 µg/mL), respectively, superior to azoxystrobin (EC50 = 12.8, 71.9, 37.2 µg/mL). Compound 5-4 displayed good activities against each of the fungi with EC50 of 10.3, 4.7 and 18.0 µg/mL while 5-34 displayed excellent activities against V. mali (EC50 = 3.9 µg/mL) and C. lunata (EC50 = 5.8 µg/mL). The SAR showed that the type and position of substituents on C-ring had significant effects on the activity. Generally, the presence of 2'-F, 4'-F or 2'-CH3 could significantly improve the activities, whereas OH, OMe, NO2 or CF3 groups decreased the activities. Thus, it was concluded that the present research provided a new series of 2-aryl-6-chloro-3,4-dihydroisoquinolin-2-iums with excellent antifungal potency and the results were of importance for the structure optimization design, synthesis and development of more potent isoquinoline antifungal agents.
    Journal of Agricultural and Food Chemistry 02/2015; 63(7). DOI:10.1021/jf505609z · 3.11 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: 6-Cyano dihydrosanguinarine (CNS) and 6-cyano dihydrochelerythrine (CNC) are respectively artificial derivatives of sanguinarine and chelerythrine, two anticancer quaternary benzo[c]phenanthridine alkaloids (QBAs) while 1-cyano-2-aryl-1,2,3,4-tetrahydroisoquinolines (CATHIQs) are a class of structurally simple analogues of CNS or CNC. This study investigated the inhibition activity of CNS, CNC and CATHIQs on cancer cells, apoptosis induction as well as their preliminary SAR. The results showed that CNS and 18 out of CATHIQs showed IC50 values of 0.53 and 0.62-2.24μM against NB4 and 1.53 and 2.99-11.17μM against MKN-45 cells, respectively, superior to a standard anticancer drug cis-platinum with IC50 of 2.39 and 11.36μM. CNC showed a higher activity against NB4 cells (IC50=1.85μM) and a moderate activity against MKN-45 cells (IC50=12.72μM). Among all CATHIQs, 2 and 17 gave the highest activity against NB4 cells and MKN-45 cells (IC50=0.62 and 2.99μM), respectively. DAPI staining, AO/EB staining and ultrastructure analysis of cells demonstrated that CATHIQs were able to induce apoptosis of the cells in a concentration-dependent manner. SAR showed that substitution patterns on the N-aromatic ring significantly influenced the activity of CATHIQs. The general trend was that the introduction of electron-withdrawing substituents like halogen atom, nitro, trifluoromethyl led to a significant improvement of the activity, while the presence of electron-donating groups like methyl, methoxyl caused a reduction of the activity. In most cases, the 2' site was the most favorable substitution position for the improvement of the activity. Thus, the present results strongly suggested that QBA-type pseudocyanides may serve as potential alternatives of anticancer QBAs while CATHIQs should be a class of promising lead compounds for the development of new QBA-like-type anticancer drugs. CNS exhibited the highest cytotoxicities with IC50 values of 0.53μM on NB4 cells and 1.53μM on MKN-45 cells. Copyright © 2014 Elsevier B.V. All rights reserved.
    European journal of pharmaceutical sciences: official journal of the European Federation for Pharmaceutical Sciences 11/2014; 67C:45-54. DOI:10.1016/j.ejps.2014.10.020 · 3.01 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: New self-assembled phosphorus ligands are synthesized and used in the rhodium complex catalyzed hydroformylation-Wittig reaction of homoallylic olefins under optimized condition. A subsequent oxa-Michael intramolecular reaction yields beta-pyran derivatives (conversion and diastereoselectivity up to 99%).
    Catalysis Communications 08/2014; 53:87–90. DOI:10.1016/j.catcom.2014.04.022 · 3.32 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: As part of our continuing research on isoquinoline acaricidal drugs, this paper reports the preparation of a series of the 2-aryl-1-cyano-1,2,3,4-tetrahydroisoquinolines with various substituents on the N-phenyl ring, their in vitro acaricidal activities against Psoroptes cuniculi, a mange mite, and discusses their SAR as well. The structures of all compounds, including 12 new ones, were elucidated by analysis of UV, IR, NMR, ESI-MS, HR-MS spectra and X-ray diffraction experiments. All target compounds showed varying degrees of activity at 0.4 mg/mL. Compound 1 showed the strongest activity, with a 50% lethal concentration value (LC50) of 0.2421 μg/mL and 50% lethal time value (LT50) of 7.79 h, comparable to the standard drug ivermectin (LC50 = 0.2474 μg/mL; LT50 = 20.9 h). The SAR showed that the substitution pattern on the N-aromatic ring exerted a significant effect on the activity. The substituents 2'-F, 3'-F, 2'-Cl, 2'-Br and 2'-CF3 remarkably enhanced the activity. Generally, for the isomers with the same substituents at different positions, the order of the activity was ortho > meta > para. It was concluded that the target compounds represent a class of novel promising candidates or lead compounds for the development of new tetrahydroisoquinoline acaricidal agents.
    Molecules 06/2014; 19(6):8051-8066. DOI:10.3390/molecules19068051 · 2.42 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Five new (4-8) and three known (1-3) dihydro-β-agarofuran sesquiterpene polyesters were isolated from the whole plants of Parnassia wightiana. The structures of all compounds were elucidated through spectroscopic analysis including 2D-NMR and HR-MS. The absolute configuration of these compounds was established by X-ray diffraction analysis, comparison of NOESY spectra and biogenetic means. The cytotoxities of compounds 2-8 were evaluated in vitro against HL-60, SMMC-7721, A549, MCF-7 and SW480 cell lines. Compounds 5-7 exhibited the highest activities with IC50 values of 11.8-30.1 μM in most cases. The SAR revealed that the introduction of hydroxyl group was able to significantly improve the activities of the compounds for most of the cell lines.
    International Journal of Molecular Sciences 06/2014; 15(6):11111-11125. DOI:10.3390/ijms150611111 · 2.46 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A new coordination polymer, [Cu3(dtb)(CN)3]n (1) (dtb = 1,3-di-(1,2,4-triazole-4-yl)benzene) based on Cu3(CN)2 clusters, has been synthesized under solvothermal conditions, and characterized by elemental analysis, infrared spectrometry, powder X-ray diffraction, thermogravimetric analysis, and single-crystal X-ray diffraction. Complex 1 exhibits a three-dimensional twofold interpenetrated net with 6-connected uninodal topology. Moreover, solid state luminescent property of 1 has been investigated at room temperature.
    Journal of Cluster Science 02/2014; 25(4). DOI:10.1007/s10876-014-0695-3 · 1.36 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: 2-Aryl-3,4-dihydroisoquinolin-2-iums might be considered as a class of simple analogues of natural quaternary benzo[c]phenanthridine alkaloids. In this paper, 26 new 2-aryl-6,7-methylenedioxy-3,4-dihydroisoquinolin-2-ium bromides with various substituents in N-aromatic ring were synthesized from commercially available 1,3-benzodioxole in good to excellent yields. All the compounds were elucidated by MS, HRMS, IR, (1)H- and (13)C-NMR analysis, and evaluated for antifungal activities in vitro against Alternaria alternate, Curvularia lunata and Fusarium oxysporum sp. niveum at 50 µg/mL. Most of the compounds showed higher activities against all the test fungi than their natural model compounds sanguinarine and chelerythrine. For A. alternate and Curvularia lunata, most of them were also more active than thiabendazole, a commercial fungicide standard. The structure-activity relationship indicated that the substituent in N-aromatic ring and its position had significant effect on the activity. The general trend was that halogen atoms and CF3 remarkably enhanced the activity while CH3 and OCH3 decreased the activity. Generally, o-substituted isomers were more active than m- and p-substituted isomer. The present results suggest that the title compounds are potential for the development of new isoquinoline antimicrobial agents.
    Chemical & pharmaceutical bulletin 01/2014; 45(1). DOI:10.1002/chin.201401174 · 1.38 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: C33H28N4O2, monoclinic, P2(1)/c (no. 14), a = 10.263(8) angstrom, b = 23.48(2) angstrom, c = 12.28(1) angstrom, beta = 114.498(9)degrees, V = 2692.9 angstrom(3), Z = 4, R-gt(F) = 0.0451, wR(ref)(F-2) = 0.1189, T = 296 K. [GRAPHICS] .
    Zeitschrift für Kristallographie. New crystal structures 10/2013; 228(3):329-330. DOI:10.1524/ncrs.2013.0160 · 0.12 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The title compounds are a class of structurally simple analogues of quaternary benzo[c]phenanthridine alkaloids (QBAs). In order to develop novel QBA-like antifungal drugs, in this study, 24 of the title compounds with various substituents on the N-phenyl ring were evaluated for bioactivity against seven phytopathogenic fungi using the mycelial growth rate method and their SAR discussed. Almost all the compounds showed definite activities in vitro against each of the test fungi at 50 μg/mL and a broad antifungal spectrum. In most cases, the mono-halogenated compounds 2-12 exhibited excellent activities superior to the QBAs sanguinarine and chelerythrine. Compound 8 possessed the strongest activities on each of the fungi with EC50 values of 8.88-19.88 µg/mL and a significant concentration-dependent relationship. The SAR is as follows: the N-phenyl group is a high sensitive structural moiety for the activity and the characteristics and position of substituents intensively influence the activity. Generally, electron-withdrawing substituents remarkably enhance the activity while electron-donating substituents cause a decrease of the activity. In most cases, ortha- and para-halogenated isomers were more active than the corresponding m-halogenated isomers. Thus, the title compounds emerged as promising lead compounds for the development of novel biomimetic antifungal agrochemicals. Compounds 8 and 2 should have great potential as new broad spectrum antifungal agents for plant protection.
    Molecules 09/2013; 18(9):10413-10424. DOI:10.3390/molecules180910413 · 2.42 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: By employing sanguinarine, a natural active quaternary isoquinoline alkaloid, as a model molecule, a series of structurally simple quaternary 2-aryl-3,4-dihydroisoquinolin-2-ium compounds were designed and synthesized and evaluated for in vitro acaricidal activity against P. cuniculi. A new approach towards the title compounds was developed with isochroman as starting material. The results showed that 22 of 24 tested compounds displayed the activity in varying degrees at 0.4 mg/mL. Fourteen compounds were significantly more effective than ivermectin, a standard acaricide, and 6-methoxy dihydrosanguinarine, a derivative of sanguinarine (P < 0.05). And their comprehensive relative activity was 1.4 to 16.5 times than that of ivermectin and 1.5 to 18.8 times than that of 6-methoxy dihydrosanguinarine. The structure-activity relationship indicated that the introduction of a substituent to N-benzene ring, especially halogen atom and trifluoromethyl group, led to great improvement of the activity. The position of fluorine atom, methyl group and hydroxyl group made very significant effects on the activity. It was concluded that 2-aryl-3,4-dihydroisoquinolin-2-iums are very promising candidates for the development of new isoquinoline acaricidal agents.
    Chemical & pharmaceutical bulletin 07/2013; 44(29). DOI:10.1002/chin.201329165 · 1.38 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Four new coordination polymers, [Co(ppmdc)(H2O)2]n (1), [Ni(ppmdc)(H2O)2]n (2), [Mn(ppmdc)(H2O)]n (3) and {[Zn(ppmdc)(H2O)2]·H2O}n (4) (H2ppmdc = 2-(pyridin-4-yl)-4,6-pyrimidine dicarboxylic acid), have been synthesized by self-assembly of the newly designed H2ppmdc ligand and corresponding metal salts under hydrothermal conditions. The four complexes exhibit versatile frameworks with different topologies due to the different metal ions and especially the diverse coordination modes of the H2ppmdc ligand. Complexes 1 and 2 exhibit 2-D layered structures with (4·82)2 and (82)2 topology, respectively, which are constructed from the self-assembly of the L- and R-type single chain helixes, in which the ppmdc2− ligand adopts a μ3-kN,O:kN′:kO′ mode to link metal ions. Complex 3 features a 3-D metal–organic framework with 5-connected (45·65)2 topology, in which the metal ions are bridged by μ5-ppmdc2− ligands. Complex 4 possesses a 2-D sheet structure with 3-connected (63)2 topology, in which the ppmdc2− ligand adopts a μ3-kN:kO:kO′ mode to link Zn(II) ions. The thermal properties of complexes 1–4, and the magnetic property of 3 have been investigated and discussed in detail.
    CrystEngComm 04/2013; 15(20):4107-4116. DOI:10.1039/C3CE00068K · 3.86 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: 1,3-Diiodotetrafluorobenzene and 1,3,5-trifluoro-2,4,6-triiodobenzene form co-crystals with 4,4′,6,6′-tetramethyl-2,2′-bipyrimidine, 1,2,4,5-tetra(3-pyridyl)benzene and 1,2,4,5-tetra(4-pyridyl)benzene in which the structural competition between ππ interactions and halogen bonds is directly observed. It is found that the strong C–IN halogen bond competes successfully with the ππ interaction between two 1,3-diiodotetrafluorobenzene molecules while the ππ interaction between two 1,3,5-trifluoro-2,4,6-triiodobenzene molecules can successfully compete with the strong C–IN halogen bond. Quantum chemical calculations explain the structural competition well.
    CrystEngComm 12/2012; 15(4):769-774. DOI:10.1039/C2CE26520F · 3.86 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: From the ethyl acetate extract of the culture broth of Talaromyces verruculosus, a rhizosphere fungus of Stellera chamaejasme L., (−)-8-hydroxy-3-(4-hydroxypentyl)-3,4-dihydroisocoumarin (1) and (E)-3-(2,5-dioxo-3-(propan-2-ylidene)pyrrolidin-1-yl)acrylic acid (2) were isolated and evaluated for their antimicrobial activities. Their structures were elucidated by UV, IR, MS, 1H-NMR, 13C-NMR and 2D NMR spectra. Compound 1 exhibited the significant activities in vitro against two strains of bacteria and four strains of fungi. Compound 2 gave slight activities on the fungi at 100 µg mL−1, but no activities on the bacteria. Compound 1 should be considered as a new lead or model compound to develop new isocoumarin antimicrobial agents.
    Molecules 12/2012; 17(12):14091-8. DOI:10.3390/molecules171214091 · 2.42 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In order to understand the antifungal activity of some derivatives of sanguinarine (S) and chelerythrine (C) and their structure-activity relationships, sixteen derivatives of S and C were prepared and evaluated for in vitro antifungal activity against seven phytopathogenic fungi by the mycelial growth rate method. The results showed that S, C and their 6-alkoxy dihydro derivatives S(1)-S(4), C(1)-C(4) and 6-cyanodihydro derivatives S(5), C(5) showed significant antifungal activity at 100 µg/mL against all the tested fungi. For most tested fungi, the median effective concentrations of S, S(1), C and C(1) were in a range of 14-50 µg/mL. The structure-activity relationship showed that the C=N+ moiety was the determinant for the antifungal activity of S and C. S(1)-S(5) and C(1)-C(5) could be considered as the precursors of S and C, respectively. Thus, the present results strongly suggested that S and C or their derivatives S(1)-S(5) and C(1)-C(5) should be considered as good lead compounds or model molecules to develop new anti-phytopathogenic fungal agents.
    Molecules 12/2012; 17(11):13026-35. DOI:10.3390/molecules171113026 · 2.42 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: IN THE CRYSTAL STRUCTURE OF THE TITLE COMPOUND [SYSTEMATIC NAME: 6,7-dimeth-oxy-12-methyl-16,18-dioxa-12-aza-tetra-cyclo-[12.7.0.0(4,9).0(15,19)]henicosa-1(21),4,6,8,14,19-hexaen-3-ol], C(21)H(25)NO(5), the benzene rings exhibits a dihedral angle of 14.95 (4)°. In the crystal, mol-ecules are linked by pairs of O-H⋯O hydrogen bonding into inversion dimers. These dimers are further connected by C-H⋯O inter-actions.
    Acta Crystallographica Section E Structure Reports Online 06/2012; 68(Pt 6):o1762. DOI:10.1107/S1600536812017588 · 0.35 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: IN THE TITLE COMPOUND (SYSTEMATIC NAME: 1,3-diiodo-4-meth-oxy-2-nitro-benzene), C(7)H(5)I(2)NO(3), the dihedral angle between the benzene ring and the nitro group is 88.0 (3)°, and the methyl group lies almost in the same plane as the ring [deviation = 0.034 (6) Å]. In the crystal, aromatic π-π stacking occurs between inversion-related rings [centroid-centroid separation = 3.865 (3) Å and slippage = 0.642 Å]. A possible weak C-I⋯π inter-action occurs [I⋯π = 3.701 (2) Å and C-I⋯π = 130.18 (13)°], but there are no significant inter-molecular I⋯I contacts.
    Acta Crystallographica Section E Structure Reports Online 05/2012; 68(Pt 5):o1500. DOI:10.1107/S160053681200952X · 0.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: AimTo investigate the total flavonoid contents and in vitro antioxidant activity of different extracts from Parnassia wightiana and their correlation.Methods50% ethanol (in water, V/V) extract from Parnassia wightiana W. was successively extracted by using 3 kinds of different solvents to provide chloroform extract (CE), ethyl acetate extract (EAE), n–butanol extract (BE) and water extract (WE). The content of flavonoids in each extract was determined using the NaNO2−Al(NO3)3-NaOH method. Different antioxidant assays (OH,· O2−,· DPPH · scavenging activity, reducing power and metal chelating activity) were employed to evaluate the antioxidant activities of four extracts, using butylated hydroxytoluene (BHT) as a reference.ResultsThe total flavonoid content in EAE was the highest, followed BE, WE and CE. WE and BE showed better antioxidant activity than CE and EAE. Each extract showed concentration dependent antioxidant activity and a high correlation between content of flavonoids and antioxidant activity.Conclusion The extrat of Parnassia wightiana W. may be used as natural antioxidant.
    Chinese Journal of Natural Medicines 05/2012; 10(3):190–195. DOI:10.3724/SP.J.1009.2012.00190
  • CHEMICAL & PHARMACEUTICAL BULLETIN 01/2012; DOI:10.1248/cpb.c12-00618 · 1.38 Impact Factor

Publication Stats

173 Citations
113.23 Total Impact Points

Institutions

  • 2014
    • Northwest University
      Northwest Harborcreek, Pennsylvania, United States
  • 2009–2013
    • Northwest A & F University
      • College of Science
      Yang-ling-chen, Shaanxi, China
  • 2008–2011
    • Rutgers, The State University of New Jersey
      • Department of Chemical Biology
      Нью-Брансуик, New Jersey, United States
  • 2007
    • Pennsylvania State University
      • Department of Chemistry
      University Park, Maryland, United States